This invention relates to remote video observation systems, and more particularly to systems for facilitating the observation of scenes or objects at substantial distances from the observer even though only relatively low-cost transmission media may be available between the original scenes or objects and the observer.
Although this invention has many other possible uses, the invention will be fully understood from an explanation of its use in identifying moving railroad freight cars at locations remote from the observer required to make the identification.
Raymond et al U.S. Pat. No. 4,264,927 (which is hereby incorporated by reference herein) shows a freight car identification system in which a remote track-side television-type camera is connected via a video signal transmission line to a centrally located videotape recorder. The system is automatically activated when a train approaches the camera and, while activated, videotapes a continuous side view of the train as it passes. As soon as the train has passed, the system shuts itself off until the next train approaches. At any convenient time, the operator of the system ("the observer") removes the recorded videotape from the recorder and plays it back on a playback machine in order to identify the freight cars in the train from the letters and numbers painted on the sides of the cars.
The system shown in the '927 patent works well and has achieved wide market acceptance. In some situations, however, it is desired to locate the camera at a considerable distance from the observer. In those instances it is usually quite costly--sometimes prohibitively costly--to provide the high-grade video communications link required between the camera and the videotape recorder. For example, railroads would frequently like to locate the camera many miles--sometimes 100 or more miles--from the observer. This may reduce the number of observation points a railroad needs by allowing greater centralization of the observation function. It may also reduce the number of employees required as observers. Heretofore, however, the high cost of long, video-grade communications links has been a major disadvantage of such otherwise desirable system configurations.
In view of the foregoing, it is an object of this invention to provide remote video observation systems which do not require high-grade communications links between the remote camera and the central observer.
It is another object of the invention to provide improved remote freight car identification systems.